Scuba tanks are an essential component of any scuba diver’s equipment. Although they are not air-filled, they do hold a large amount of gas. The tank size will vary depending on what type of diving you do. You'll need to select the right tank based upon the water type you intend to use. Below are the main types, as well as their sizes.
scuba tanks contain no air
The standard aluminum 80 can holds 77 feet3 air. Trimix, which is a type diving gas, has a 10 to 20% lower capacity than air. Also, higher maximum service pressures don't necessarily equal more air. Although manufacturers often exaggerate their tanks' capacity. It is worth comparing the capacity of each cylinder with the actual volume.
They contain a volume of free gas greater than their water capacity
Technical divers use mixed gases differently to recreational divers. Their true air and Trimix capacities, however, are lower than their actual water capacities. For example, Helium is more compressible than air so their true air and trimix capacities are lower than their water capacities. Double HP117 cylinders contain a true air volume of 235 ft3 while Heliair 10/50 has a true air capacity of 216 ft3. Use the Z Factors to determine the correct mixed gas capability.
They are made out of steel and aluminum
Consider the needs of divers when choosing between an aluminum or steel scuba tank. Steel tanks are more robust and can withstand deeper underwater dives. This durability comes at a price. Aluminum tanks can easily develop structural fractures which can lead to serious injury. Additionally, an aluminum tank will cost more than a steel one. Aluminum tanks, however, are now the industry standard.
You can get them in many sizes.
Scuba tanks can be made from two materials: aluminum or steel. Steel tanks are lighter and more durable, but tend to weigh more. If you plan on doing a lot of diving and plan to bring a weight belt, it might be best to go with an aluminum tank. Aluminum tanks may not be as light as steel tanks so it is important to know your weight requirements before you purchase one. Steel tanks work well for drysuit and local diving.
They must be inspected often
There are many methods to test your scuba tanks. Hydrostatic testing is usually stamped into the metal beneath the neck of the tank. An inspection visually can help you detect corrosion or contamination. Tumbling is another way to check the condition of your tank. Tumbling involves filling the tank with media and spinning it for a time to get rid of dirt and other contaminants. It may be necessary to clean the tank if it sounds rough.